The present invention relates to a liquid crystal display, and more particularly relates to improvement in molecular orientation of a liquid crystal display generally used for video display panels such as television sets.
A liquid crystal display is in general provided with a alignment film (alignment layer) for liquid crystal molecular orientation in a prescribed direction. Conventionally, such an alignment film is classified into two major types, i.e. an organic film prepared by the rubbing process and an evaporated film (thin film) prepared by the oblique evaporation.
In the case of the organic film, a film of polyimide, polyamide or polyvinyl alcohol is formed on a substrate via spinner process or print process and the organic film is rubbed. In the case of the evaporated film, an oxide, i.e. a silica oxide such as SiO and SiO.sub.2 or an magnesium fluoride such as MgF.sub.2, is deposited onto an inclined substrate.
A liquid crystal display containing the above-described organic alignment film can be easily produced and exhibit stable molecular orientation when used for the TN (twisted nematic) liquid crystal system. Despite the merit, the display is quite unsuited for molecular orientation of a large pretilt angle which is needed for memory type ferroelectric liquid crystal components and STN (super twisted nematic) type liquid crystal components.
A liquid crystal display containing th above-described evaporated film can exhibit molecular orientation of relatively large pretilt angle. Despite its merit, it is difficult to produce a uniform alignment film which is necessary for good reproduction and stability of orientation in the cause of large image surfaces. In addition, its production efficiency is rather low.